In terms of the atomic origin of these single-photon emitters, annular dark-field images have shown that carbon substitutions are abundant in hBN [1]}.
Recently, Mendelson et al. [2]} has identified that various techniques of incorporating carbon into hBN yield \(\sim \) 2 eV single-photon emitters.
Moreover, X-ray photoelectron spectroscopy measurements show that more C-B bonds exist than that of C-N bonds [2]}. This is an evidence that carbon substitution of nitrogen is more likely than carbon substitution of boron.
